EP0606585B1 - Severing- and clamping device for front yarn, for embroidering machines - Google Patents

Abstract

A cutting apparatus for embroidery machines that facilitates the positive cutting of the threads at the end of each embroidery operation. Large-scale embroidery machines may provide several hundred embroidery positions, and each position is provided with an individually-actuable cutting and gripping device. These individual cutting mechanisms are in turn collectively mounted on one or more feeder bars that permit the pivotal movement of the cutter/grippers into and away from a position in close proximity to the embroidery needle stitch points. This pivotal movement permits the close cutting of the thread when required, yet otherwise locates the thread cutter/grippers at a position away from the stitch points during the embroidery operation itself.

Description

In large embroidery machines with a few hundred embroidery points, cutting and pinching the embroidery threads by hand is tedious and brings long downtimes. In addition, the embroidery threads on the front should be cut clean and as close as possible to the embroidery base to save on the additional shearing process. Such a cutting and clamping device also has great advantages when programming and embroidering color or repeat change patterns. Cutting and clamping devices that were developed for sewing machines or multi-head embroidery machines cannot be adapted. They are too large for the standard needle spacing of 27.01 mm (= 1 French inch) and too complex and expensive for use at hundreds of embroidery sites.

CH 577 587 (Pfaff) shows such a device on multi-head embroidery machines for clamping and cutting the needle thread. With 500 to 1000 embroidery points on a large embroidery machine at a distance of 27.01 mm, such a device is hardly economically viable in terms of cost and space.

CH 536 893 (Metalmeccanica) describes a cutting device for the front yarns on a large embroidery machine. A knife is attached to a sled. The carriage is moved parallel to the plane of the fabric over the entire length of the machine, the front threads being cut one after the other. A clean cut can only be made if the front threads are taut. Hundreds of threads have to be cut from the same knife with each cutting process, which leads to rapid blunting. When cutting with this device, a lateral force acts on the thread at the moment of cutting, which can lead to warping in the embroidery. The thread is jammed in this device not possible. A cutting device without thread clamping is not usable with embroidery machines, since most threads would come out of the needles in a short time.

CH 647 283 (Heinzle) shows a simple cutting and clamping device that can be attached to the fabric presser for each needle. It is not to be expected that the threads will be cut reliably due to the relatively slow lateral movement of the embroidery frame. Due to the constant, abrupt impact of the presser on the fabric in the embroidery mode, the cutting and clamping elements can be released or destroyed over time.

DE-0 35 02 886 (Reich) shows cutting elements arranged on a shaft. By turning this shaft, the cutting elements are pressed onto the fabric and moved on the fabric. With this sliding movement, the thread is to be cut by a single knife edge. Thread clamping is not provided.

In contrast, the invention provides a cutting and clamping device for large embroidery machines, which can be implemented in terms of expenditure and space, which solves the entire problem of clamping, cutting and re-sticking, and which, by arranging 2 counteracting, actively operated cutting edges, ensures safe cutting of all Threads.

An essential feature of the present invention is that in a large embroidery machine the cutting and clamping elements are present in large numbers and each cutting point is assigned a cutting and clamping element. This has the advantage of individual control of the cutting and clamping elements, because it is provided in a development of the invention that the cutting and clamping elements can be controlled separately.

The feature of the invention is therefore that each thread to be cut is first clamped before the cutting process in order to be cut off afterwards. This has the advantage that the thread is only cut in the clamped state and is thereby held securely. This has the advantage that the thread is brought into a rest position in the clamped state. This avoids that the thread can unthread and the cutting and clamping device according to the invention is placed at a distance from the plane of the fabric, i.e. away from the fabric level, which has the advantage that it no longer rubs along the fabric and possibly leads to damage.

In a further development of the invention it is provided that the cutting and clamping element works with a movable knife and with a fixed knife. This has the advantage that a cutting effect is achieved as with scissors. This results in a precise cut and there is no tension on the thread, which could undesirably distort the fabric.

Due to the advantage that the cutting and clamping device is located at a short distance (e.g. 1 mm) in front of the fabric plane during the cutting process, there is the advantage of a short thread end and therefore the cut thread ends no longer have to be processed in a further operation.

Since all clamping elements are attached to a rail, all clamping elements can be operated with a single, possibly continuous rod. This is associated with the advantage of low machine outlay and correspondingly low manufacturing and maintenance outlay.

The essence of the invention is that the actively operable Cutting and clamping elements with their mounting rail can be brought from an idle position, which is distant from the plane of the fabric, to an active position near the nitrogen and can be moved back to their idle position. Thus there is the above-mentioned advantage that in the rest position the cutting and clamping elements are removed from the fabric and cannot collide with it, while in the cutting position the cutting and clamping elements practically rest on the fabric and extremely short thread ends remain on the fabric.

The above-mentioned mounting rail executes a parallelogram movement which is designed as a pivoting movement in one plane, which is perpendicular to the fabric web.

This parallelogram movement has the advantage that the fabric is moved from the rest position and at the same time a lateral approach movement to the piercing point of the embroidery needle takes place.

The subject matter of the present invention results not only from the subject matter of the individual patent claims, but also from the combination of the individual patent claims with one another. All of the information and features disclosed in the documents, including the summary, in particular the spatial design shown in the drawings are claimed to be essential to the invention, insofar as they are new to the prior art, individually or in combination.

The invention is explained in more detail below with the aid of drawings which illustrate only one embodiment. Here, from the drawings and their description, further features and advantages of the invention that are essential to the invention emerge.

Fig. 1 a,b,c,d:

Ansicht und Draufsicht eines Abschnittes einer Tragschiene mit Schneid- und Klemmelementen in Position "Vorn" und "Hinten", wobei Fig. 1c schematisiert den Bewegungsablauf der Tragschiene zeigt und Fig. 1d den Bewegungsablauf der Schneid- und Klemmelemente;

Fig. 2 a,b:

Ansicht eines Abschnittes einer Tragschiene in den zwei Positionen "Vorn" und "Hinten" und Querschnitt der Tragschiene;

Fig. 3 a,b:

Vorder- und Seitenansicht eines Schneid- und Klemmelementes;

Fig. 4:

zeigt schematisiert den Antrieb des beweglichen Messers mit Zahnradgetriebe.

Show it:

1a, b, c, d:

View and top view of a section of a mounting rail with cutting and clamping elements in the "front" and "rear" positions, with FIG. 1c schematically showing the movement sequence of the mounting rail and FIG. 1d showing the movement sequence of the cutting and clamping elements;

2 a, b:

View of a section of a mounting rail in the two positions "front" and "rear" and cross section of the mounting rail;

3 a, b:

Front and side view of a cutting and clamping element;

Fig. 4:

shows schematically the drive of the movable knife with gear transmission.

FIG. 1 shows a section of a mounting rail 2, which in the case of large embroidery machines extends over an embroidery length of a few hundred embroidery needles. These embroidery needles 3 are arranged linearly in the needle repeat 4 by a French inch (27.01 mm). Cutting and clamping elements are attached to the mounting rail 2, so that each embroidery needle 3 or each embroidery point is assigned a cutting and clamping element. During the embroidery process, the embroidery tools (embroidery needles 3; drills) must work freely and without hindrance. The mounting rail 2 is therefore in the "rear" position (fully extended in FIG. 1).

The cutting and clamping element consists essentially of a fixed knife 15, which with retaining bolt 40 the vertical leg of the mounting rail 2 is attached. A movable knife 16 is guided on the fixed knife 15 in a longitudinally displaceable manner in the arrow directions 21, 22 via a parallel guide 17, which consists of hollow rivets and correspondingly elongated recesses. The clamping spring 18 is fastened to the fixed knife 15 and forms a clamping gap in relation to the movable knife 16, which is defined by the spring end 35 on the one hand and by a corresponding front of the movable knife on the other.

The clamping spring 18 has the further task of avoiding any inadmissible play between the movable and fixed knives 15, 16 by pressing the movable knife against the fixed knife, and thus the scissor-like cutting effect is always maintained, regardless of the wear of the Knife 15.16.

According to FIG. 3b, the thread 33 to be cut is passed through the eye 34 of the embroidery needle 3 and is clamped and held in the form of a thread end 42 in the clamping point (spring end 35).

FIG. 3b actually shows the position of the movable knife 16 in a raised position (arrow direction 21) when the entire cutting and clamping element 1 moves from a rest position according to FIG. 1d (left) to the cutting position (FIG. 1d - right) and in this case, with the movable knife 16 raised, the lateral recess 19 of the movable knife is moved over the thread 33 to be cut and receives it in the recess 19.

Only then does the movable knife 16 move downward in the direction of the arrow 22, clamps the thread in the spring end 35 and then cuts in the same movement.

It is important here that when the movable knife 16 is moved down, this thread to be cut first arrives in the region of the spring end 35 and is held there, the corresponding edges on the side of the movable knife facing the spring end 35 being polished so that they are clean. are rounded so that no cutting process can take place in this area. For this reason, the thread 33 is clamped on the spring end 35 on this side (in FIG. 3b - right), while on the opposite side (FIG. 3b - left) there is the knife edge 37 of the movable knife, which corresponds to the assigned knife edge 36 of the fixed one Knife 15 performs the cutting process.

The movable knife 16 is displaced in the arrow directions 21, 22 by the action of a sliding piece 12, which engages with a groove 31 pointing in the longitudinal direction of the mounting rail 2 over a bent tab 32 of the movable knife 16.

The sliding piece 12 is driven to be displaceable in the arrow directions 21, 22. In order to achieve an easy interchangeability of the cutting and clamping element, it can be provided that the groove 31 can be opened by e.g. the sliding piece 12 is made in two parts in the region of the groove 31, to remove the upper part and thus to pull the entire cutting and clamping element 1 upward from the retaining bolts 40 in the direction of the arrow 21.

The sliding piece 12 is firmly connected to a bolt 11.

The sliding piece 12 is slidably mounted in a recess in a vertical direction (FIG. 2b) in a stationary guide rail 25. Because of the cut This vertical recess, in which the sliding piece 12 is slidably mounted, cannot be seen in FIG. 2b.

The guide rail 25 consists essentially of a U-shaped profile which accommodates the displaceable drive rod 7 in its interior perpendicular to the plane of the drawing in FIG. 2b.

According to Figures 1 a and 2 a, a series of spaced-apart pivot points 9 are arranged in the drive rod 7, which are designed in the form of bolts and each pivotally receive an angle lever 8.

The angle lever 8 consists of two swivel arms, each swivel arm having an elongated hole 29, 43. The one elongated hole 29 serves for the displaceable engagement of a locking bolt 10, which is displaceable in the direction of arrow 23 and in the opposite direction in FIG. 2b. For this purpose, the locking bolt 10 sits in a bore 28 in a cover 27, which cover 27 is part of the guide rail 25 and is firmly connected to it.

A slide 13 engages in the bore 28 and is connected to a shift lever 14 of the embroidery position circuit.

The mounting rail 2 carries out the previously mentioned parallelogram movement, which movement is shown schematically in FIG. 1c. For this purpose, it is important that the pivot levers 6 are connected to the guide rail 25 at the pivot point 5, the free pivotable ends of which are connected to the mounting rail 2.

Thus, the mounting rail 2 performs a parallelogram-like displacement due to the pivoting movement on the pivot levers 6 1c and thus assumes a position "front" in the direction of the arrow 38 close to the fabric and a position "rear" in the direction of the arrow 39 raised from the material and removed from the embroidery needle.

Characterized in that the cutting and clamping elements 1 are firmly connected to the mounting rail 40 via the retaining bolts 40, the cutting and clamping elements accordingly perform the aforementioned parallelogram-like shift.

The mounting rail 2 is guided locally on stationary holders 26 which are fastened to the guide rail 25. Accordingly, the mounting rail 2 is displaceable both in the arrow directions 23, 24 and perpendicularly to it in the arrow directions 38, 39, which leads to the above-mentioned, superimposed parallelogram-like displacement movement of the mounting rail 2 and thus all cutting and clamping elements 1.

The brackets 26, which are attached to one another at intervals on the underside of the guide rail 25 (FIG. 2a), serve to additionally guide the mounting rail. This achieves a play-free guidance of the cutting and clamping elements in the direction of the material plane 20 and in the opposite direction.

FIG. 2b shows the position of the cutting and clamping elements which is raised from the material plane 20.

The embroidery needles 3 are held interchangeably in needle carriers 41, which needle carriers 41 are held in a guide and which are slidably guided perpendicular to the fabric plane 20.

If it is necessary to cut the threads, the mounting rail 2 is moved in a "forward" position. brought and are then positioned close to the plane of the fabric so that the last puncture point of the needle is in the lateral recess 19 of the movable knife 16.

The clamping and cutting process is shown in Fig. 2,3. The movable knife 16 is pushed upward so that the needle axis (= puncture points) comes to rest in the lateral recess 19. This opening of the knife can take place before the mounting rail 2 with the cutting and clamping elements 1 is brought into the working position at the front. The opening of all knives, i.e. the movement of the movable knives 16 is triggered by the drive rod 7. When the drive rod is displaced horizontally to the right, the locking lever 8 is prevented by the locking bolt 10 from participating in the movement of the drive rod in a constant position. Since one lever arm is held back by the locking bolt 10, the angle lever 8 rotates about the pivot point 9 and thus pushes the bolt 11 upward with its second arm. The bolt 11 is firmly connected to the sliding piece 12. With a groove 31, the movable knife 16 is moved upwards by the sliding piece. After the last needle insertion, the movable knife 16 is pulled down by a horizontal movement of the drive rod 7 when the front thread is tensioned. This movement pulls the front thread under the clamping spring 18 and then cuts through the cutting edges of the movable knife 16 and the fixed knife 15. The parallel guide 17 ensures that the movable knife 16 moves exactly parallel to the fixed knife 15 and thus guarantees a clean thread cut between the cutting edges.

A cut thread remains in the clamping between the clamping spring 18 and the movable knife 16 until the next stitching. The mounting rail 2 with the cutting and clamping elements 1 is moved back to the "back" rest position.

When you start sewing again, the mounting rail 2 goes into the working position "front" with all cutting and clamping elements 1; the cutting and clamping elements lie directly on the fabric. After the first piercing stitches, the movable knife 16 goes up and thus releases the thread end held under the clamping spring 18. The cutting and clamping elements 1 go back to their "back" rest position. Because the cutting and clamping elements 19 lie directly on the fabric, both when cutting and when embroidering, the rest of the thread end is so short that a subsequent operation (shearing the thread ends) is not necessary.

With a so-called embroidery point circuit, individual embroidery points can be coupled to or decoupled from the drive, so that a specific combination of embroidering and non-embroidering embroidery points is defined. The thread cut should not work with non-embroidering embroidery areas. This is achieved by pulling back the locking bolt 10. When the drive rod 7 moves to the left or right, the one lever arm of the angle lever 8 is therefore no longer locked. It therefore no longer rotates about the pivot point 9 and the movable knife 16 is not driven via the pin 11, i.e. the clamping and cutting process does not take place at this embroidery site.

The locking bolt 1 can be set or withdrawn using the existing embroidery point circuit or its switching lever 14 via the connection 3. However, separate actuators (magnets, ...) can also be provided for this.

With the above explanation is a selection process described how the locking pin 10 is set or not set by actuating the switching lever 14 of the embroidery position circuit. Setting the locking bolt means that it is displaced in the direction of arrow 30 to the left in its bore 28, so that it engages in the associated elongated hole 29 of the angle lever 8 and thus couples the angle lever 8 to the displaceably driven mounting rail. As previously mentioned, the angle lever 8 is pivotally mounted in a recess 44 in the region of the guide rail 25 about the pivot point 9.

When the locking bolt 10 engages in the elongated hole 29 of the angle lever 8, this one pivot arm is fixed with its elongated hole 29 on the stationary guide rail 25 and thus forms a stationary pivot point about which the angle lever 8 pivots when the carrier rail 2 in the arrow directions 38 , 39 is moved.

As already mentioned before, the pin 11 is firmly connected to the sliding piece 12 and this pin engages in the elongated hole 43 in the opposite pivotable lever end of the angle lever 8.

In Figure 2a, the two different pivot positions of the angle lever 8 are drawn, where it can be seen that when the drive rod 7 is displaced in the direction of arrow 38, the angle lever is pivoted about the stationary locking bolt 10 and at the same time the bolt 11 is upward (arrow direction 21). is displaced, whereby the sliding piece 12 is raised, which in turn shifts the displaceable knife 16 upward in the direction of arrow 21.

• 1. Ein Auswahlmechanismus für die arbeitenden und nicht arbeitenden Stickstellen, welcher Auswahlmechanismus über den Schalthebel 14 und den Schieber 13 erfolgt, welcher den Arretierbolzen 10 betätigt.
• 2. Eine Öffnungsbewegung des Messers, wobei bei dieser Bewegung das Schiebestück 12 in der vorher beschriebenen Pfeilrichtung 21 verschoben wird und das bewegliche Messer 16 in die Stellung nach den Figuren 3a und 3b gebracht wird.
• 3. Eine parallelogrammartige Verschiebung aller Schneid- und Klemmelemente, die auf einer gemeinsamen Tragschiene 2 angeordnet sind mit einer überlagerten Schwenkbewegung in den Pfeilrichtungen 23,24 bzw. 38,39 in Richtung zur Stoffebene 20 und in Gegenrichtung hierzu.

There are three functions in the arrangement according to the invention, namely:

• 1. A selection mechanism for the working and non-working embroidery sites, which selection mechanism takes place via the shift lever 14 and the slide 13, which actuates the locking bolt 10.
• 2. An opening movement of the knife, with this movement the sliding piece 12 being displaced in the arrow direction 21 described above and the movable knife 16 being brought into the position according to FIGS. 3a and 3b.
• 3. A parallelogram-like displacement of all cutting and clamping elements which are arranged on a common mounting rail 2 with a superimposed pivoting movement in the arrow directions 23, 24 and 38, 39 in the direction of the material plane 20 and in the opposite direction.

The drive rod 7 is driven so as to be displaceable in the direction of displacement 38, 39 by an electromagnetic, pneumatic or hydraulic drive. This displacement drive is not shown in the drawings and is familiar to a person skilled in the art.

In the above description, a common actuation of all cutting and clamping elements by a common drive rod 7 has been described. It is within the scope of the present invention and is also claimed as essential to the invention that instead of the drive rod 7 described, there is an individual drive for each individual cutting and clamping element, the drive rod 7 then being replaced by corresponding actuators which act directly on the sliding pieces 12 with their actuating element attaches and move them in the direction of arrows 21,22.

In the above description, the focus was on the cutting and clamping elements 1 executing a parallelogram-like feeding and lifting movement from the fabric plane 20, which has the advantage that the cutting and clamping elements 1 are removed from the fabric plane in the rest position.

In another embodiment (claim 10), it is provided in a simpler design that instead of the infeed and away movement of the cutting and clamping elements to the fabric plane, they remain constantly close to the fabric plane 20 and there is no lifting movement. This design is then mechanically simpler and solves the same task of the invention.

According to claim 11 it is provided that the drive rod 7 is guided in a longitudinally displaceable manner in a recess of the U-shaped profiled guide rail.

In an alternative embodiment according to claim 12 it is provided that the drive rod 7 is guided in a longitudinally displaceable manner on the mounting rail 2; guidance in the guide rail 25 is then omitted.

In Figure 4 with reference to claim 15 it is shown that the horizontal longitudinal movement of the drive rod 7 is transmitted via a toothing on the drive rod 7 to the movable knife 16, wherein a fixed gear 45 engages in a toothing on the sliding piece 12 and thus the displacement movement converts the drive rod into a vertical clamping and cutting movement.

Claims (22)

1. Cutting and clamping device for front yarn for embroidering machines having a relatively large number of needles (3) arranged in a row or in a plurality of rows, a large number of actively actuable cutting elements being fastened to a common carrier rail (2) at the spacing of the needle gauge, characterized in that a large number of actively actuable clamping elements (1) are fastened to the common carrier rail (2) at the spacing of the needle gauge (4).
2. Cutting and clamping device according to Claim 1, characterized in that these actively actuable cutting and clamping elements (1) can be moved, together with their carrier rail (2), from a position of rest into an active position near the embroidery material and near the pricking point of the needles (3) and back again into the position of rest.
3. Cutting and clamping device according to Claim 2, characterized in that the cutting and clamping tools in all the cutting and clamping elements (1) are actuated by means of a common mechanically connected drive (7).
4. Cutting and clamping device according to Claims 1 and 2, characterized in that the cutting and clamping members are actuated by means of an actuator assigned to each cutting and clamping element (1).
5. Cutting and clamping device according to one of the preceding Claims 1 to 4, characterized in that, by means of a selection mechanism, only specific cutting and clamping elements (1) are connected to the common drive of the cutting and clamping members.
6. Cutting and clamping device according to Claim 4, characterized in that, by means of a selection circuit, only specific actuators are actuated.
7. Cutting and clamping device according to one of Claims 1 to 6, characterized in that the cutting and clamping elements (1) are fastened to the carrier rail (2) in such a way that they can easily be exchanged individually as an entire element.
8. Cutting and clamping device according to one of Claims 1 to 7, characterized in that the carrier rail (2) is fastened pivotably at two or more points (5), so that the cutting and clamping elements (1) fastened to it are guided, in a parallelogram-like displacement of the carrier rail (2), up to the embroidery material and simultaneously into the vicinity of the needle pricking points and from there are guided back again into the position of rest.
9. Cutting and clamping device according to one of Claims 1 to 8, characterized in that the carrier rail (2) is divided over the entire length of the machine into separate modules/sections which can be individually assembled, mounted and moved.
10. Cutting and clamping device according to one of Claims 1 to 9, characterized in that the cutting and clamping elements (1) are constantly located close to the embroidery material and the carrier rail (2) is guided in such a way that the cutting and clamping elements (1) are displaced parallel to the material plane (20) into the region of the needle pricks and out of this region.
11. Cutting and clamping device according to one of Claims 1, 2 or 3, characterized in that the common drive of the cutting and clamping members consists of a drive rod (7) which is guided so as to be longitudinally displaceable parallel to the carrier rail (2) in a recess of a fixed guide rail (25).
12. Cutting and clamping device according to one of Claims 1 to 10, characterized in that the drive rod (7) is guided on the carrier rail (2).
13. Cutting and clamping device according to one of Claims 1 to 12, characterized in that the drive rod (7) is divided into sections which each have their own drive.
14. Cutting and clamping device according to one of Claims 1 to 13, characterized in that the horizontal longitudinal movement of the drive rod (7) is converted into a vertical clamping and cutting movement via a toothing on the drive rod (7), a fixedly mounted gearwheel (45) and a toothing on the movable knife (12).
15. Cutting and clamping device according to one of Claims 1 to 14, characterized in that the horizontal movement of the drive rod (7) is converted into a vertical movement of the movable cutting knife (16) by means of a two-armed angle lever (8) which is capable of rotating on the drive rod (7), one arm of the angle lever (8) being retained by a retaining bolt (10) in such a way that the angle lever (8) executes a rotational movement as a result of the displacement of the drive rod (7) and brings about the vertical displacement of the movable knife (16) via a bolt (11) which is connected to the latter.
16. Cutting and clamping device according to one of Claims 1 to 15, characterized in that the retaining bolt (10) which retains one lever arm of the angle lever (8) can be displaced along its axis in such a way that the said arm of the angle lever (8) is no longer retained, and, as a result, no rotational movement of the angle lever (8) takes place, with the consequence that the vertical movement of the movable knife (16) on the corresponding clamping and cutting element (1) also ceases.
17. Cutting and clamping device according to one of Claims 1 to 16, characterized in that the axial adjusting movement of the retaining bolt (10) is achieved by means of electromagnets or pneumatic or hydraulic cylinders.
18. Cutting and clamping device according to one of Claims 1 to 17, characterized in that the axial adjusting movement of the retaining bolt (10) is picked up by an embroidery point circuit.
19. Cutting and clamping device according to one of Claims 1 to 18, characterized in that the cutting and clamping device consists, on the one hand, of a fixed knife (15) which is fastened to the carrier rail (2) and, on the other hand, of a movable knife (16) which, driven by the common drive rod (7), executes a vertical cutting and clamping movement along the longitudinal axis of the two knives (15, 16).
20. Cutting and clamping device according to one of Claims 1 to 19, characterized in that the movable knife (16) is guided in parallel on the fixed knife (15).
21. Cutting and clamping device according to one of Claims 1 to 20, characterized in that a clamping spring (18) fastened to the fixed knife (15) presses onto the movable knife (16) and, during the cutting operation, the embroidering yarn (33) is drawn into the clamping region (35) as a result of the knife movement.
22. Cutting and clamping device according to one of Claims 1 to 21, characterized in that the movable knife (16) has a lateral cutout (19), so that the clamping and cutting element (1) can be brought from the side into the region of the needle prick in such a way that the needle yarn (33) extending from the prick comes to rest in the region of the cutting and clamping members (1).

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